DIAGONAL, HARMLESS and SUNSHINE are EU-funded Horizon 2020 projects addressing the call topic “Safe by design, from science to regulation: multi-component nanomaterials”. The three sister projects joined forces since the very beginning, in 2021, collaborating on the challenges related to safe and sustainable multicomponent nanomaterials (MCNMs). This poster was created jointly by the three projects to inform the broader community about their collaborative approach. For cross-cutting topics, so-called “Ambassadors” were appointed to facilitate cross-project knowledge exchange and scientific discussion. The installed task forces formed by the Ambassadors representing each of the three projects were well embedded in the EU NanoSafety Cluster ecosystem and can serve as best practice example of efficient and fruitful cross-project collaboration. This poster was presented at the NMBP-16 booth during the NanoTox 2024 conference (23-25 September 2024, Venice, Italy). Acknowledgement: These projects have received funding from the European Union’s HORIZON 2020 Research & Innovation Programme under grant agreement n° 953152 (DIAGONAL), n° 953183 (HARMLESS) and n° 952924 (SUNSHINE).